1. Field of the Invention
The present invention relates generally to measuring devices used to measure vehicle bodies being repaired following collisions, and more particularly, to a vehicle repair measuring device which quickly compares distances between one or more known reference points on the vehicle body and pairs of vehicle body components that are normally equidistant from such reference points.
2. Description of the Prior Art
A variety of manufacturers supply vehicle collision repair systems for pulling vehicle body frames to return the vehicle body to proper alignment following a collision. It is particularly important for the front end of a vehicle involved in a collision to be in proper alignment to ensure proper steering and performance of the vehicle. Accordingly, pulling vehicle body frames tends to be an iterative process wherein the body is first measured to determine in which direction or directions the body has been deflected from true alignment. Once the general direction of correction is known, a first pull is made in the direction of correction, and the body is measured again to see if further correction is needed.
Many car manufacturers have adopted unibody designs for vehicles. In a unibody design, the floor, structural body components, suspension, and drive train mounting components are merged into an integral unit. Unibody construction offers increased safety to passengers within the car in the event of a collision. Collision forces are transferred throughout the unibody structure to better absorb such forces. Accordingly, if a vehicle is involved in an accident, it is important that repairs be made to restore the unibody structure to its original condition, within factory specifications, so that it can again properly absorb collision forces in the event of a second accident.
Measurements on a damaged vehicle body are often made relative to an imaginary centerline passing through the vehicle along the longitudinal axis of the vehicle. The centerline is an imaginary vertical plane running from the front to the rear of the vehicle and dividing the vehicle left to right. Manufacturers often specify measurements relative to symmetrical reference points, i.e., bolts or other vehicle components that are equidistant from the centerline. However, this centerline is, in fact, imaginary, and often, there are no convenient bolts or other reference points on the vehicle body to indicate where the centerline actually lies.
Vehicle manufacturers typically publish specifications indicating nominal distances between various components on the vehicle when the vehicle is properly aligned. For example, a car manufacturer might specify that the distance between a left front hinge bolt and a bolt located on the right front fender is 1655 millimeters, and that the distance between the right front hinge bolt and the corresponding bolt located on the left front fender is also 1655 millimeters. In this event, the body shop repairman can measure the two distances with a tram bar and see if they are equal or not. However, such dimensions are not always uniform or symmetrical. For example, a car manufacturer may specify proper underhood dimensions relative to a windshield wiper pivot bolt that is offset from the centerline of the vehicle; in such instances, the specifications may state that the distance between the wiper pivot bolt and a bolt secured to a front left fender is 1088 millimeters, while the distance from the same wiper bolt to the corresponding bolt secured to the right front fender is 1068 millimeters.
Simple tram bars have been available to aid in making point to point measurements on the vehicle body. For example, one such tram bar is commercially available from Dent Fix Corporation of El Segundo, Calif. under the trade designation "DF-3D DigiTram". The tram bar is telescopic and digitally displays the distance between the ends of the tram bar. More commonly, such telescopic tram bars having simple ruled markings have long been used by repairman to make point to point measurements. One problem encountered by repairman when using tram bars to make measurements between pulls is that the tram bar is not supported by the vehicle, and accordingly, the tram bar must be removed from the vehicle and set aside while the repairman makes the additional pull. This process must be repeated several times and becomes a nuisance.
Car repair equipment manufacturers have devised elaborate measuring systems for use with collision repair systems in order to make measurements during the process of pulling and aligning the vehicle body. One such system is marketed by Continental Collision Repair Systems of Alexandria, Minn. under the trade designation "Universal Measuring System". Promotional literature for such system indicates that it is covered by either U.S. Pat. Nos. 4,442,608 or 4,490,918. The measuring apparatus includes a great number of support arms that extend from below the vehicle, around the sides of the vehicle, and across the top of the vehicle. While such measuring systems can permit a variety of measurements to be made once the system is erected about the car, it may take hours to initially set up the assembly of support arms around the damaged vehicle. A similar measuring system has been commercially available from Chief Automotive Systems Inc. under the trade designation "Dimension III". This system likewise employs a series of base rails, longitudinal rails, vertical rails, and upper body gages which extend about the entire vehicle and require significant set-up time. Likewise, a similar system is marketed by Autorobot Finland Ky of Kuopio, Finland under the trade designation "AUTOROBOT". In addition, Grabber Manufacturing Co., Inc. of Brunswick, Ga. markets a frame pulling apparatus for vehicles under the designation "G-Force 2000" which is available with an "Ultra-Spec 2000" measuring system which extends around the sides of the vehicle and above the vehicle to make body measurements.
U.S. Pat. No. 3,869,804 to Friend describes a vehicle frame alignment gage to straighten a vehicle to its original alignment. The apparatus is supported under the damaged vehicle and includes a number of support beams. U.S. Pat. No. 4,165,567 to Olsson discloses a similar measuring device. U.S. Pat. No. 4,015,339 to Horallius describes a telescopic measuring tool for indicating the centerline of the vehicle frame at a point offset from the frame itself. U.S. Reissue Pat. No. Re. 32,926 describes a rectangular frame gauge extending below, around, and above the front end of a damaged vehicle. Similarly, U.S. Pat. No. 4,329,784 to Bjork discloses a device for checking the dimensions of damaged vehicles, again using a series of beams extending under and around the vehicle. U.S. Pat. No. 4,386,468 describes an automobile frame aligning device including a base extending under the vehicle and a vertical support to which one or more scales are secured. U.S. Pat. No. 4,771,544 issued to Riutta describes a vehicle body measuring apparatus wherein a pair of telescoping arms are pivotally mounted on either side of the damaged vehicle from underneath the vehicle. A top bar is connected between the upper ends of the side arms, and a pair of pointers are slidably mounted on the top bar. U.S. Pat. No. 4,939,848 issued to Armstrong describes a vehicle frame alignment gauge or tram bar for use in checking the alignment of a vehicle frame. The disclosed device includes a telescoping adjustable length beam and two needle indicators; bubble levels are included on one of the beams of the device to ensure that the beam is truly horizontal or vertical. Armstrong describes placing one of the needle indicators on a bolt located on the centerline of the vehicle, extending the second needle indicator to contact one of the front bumper supports, and then rotating the tool to contact the other front bumper support. Of course, this technique will not work if there is no bolt or other component that can serve as a convenient reference point on the centerline of the vehicle body.
A computerized form of measuring system for estimating vehicle repairs is commercially available from Continental Manufacturing, Inc. of Alexandria, Minn. under the trade designation "COMS 2000". Promotional literature for such system indicates that it is covered by U.S. Pat. No. 4,473,954. The measuring apparatus includes a computer, a pointer probe accessory for pointing at a given vehicle component, a sensor stand supporting a positioning sensor responsive to the probe, and a remote transmitter for controlling the computer.
While some collision repair equipment manufacturers have opted for high technology solutions to measure the vehicle body, including computers, infrared sensors and/or lasers, such systems are expensive and are out of reach of many body shops. In addition, elaborate measuring systems can be bulky and take up significant space within a shop, where space is often at a premium. In addition, repair shops prefer measuring equipment which can quickly and easily be moved from one portion of the shop to another, and from one vehicle to another so that maximum use of such equipment can be made, and so that more vehicles can be repaired in a given amount of time.
Accordingly, it is an object of the present invention to provide a vehicle repair measuring device which is inexpensive and which quickly and easily indicates whether a vehicle which has suffered a collision has been pulled back into proper alignment.
It is another object of the present invention to provide such a measuring device which can be quickly erected for taking measurements on a vehicle, whether such vehicle is free-standing or mounted on a collision repair system, and which can be quickly removed after measurements are completed.
It is still another object of the present invention to provide such a measuring device which may be left in place while pulls are made to the vehicle body by a collision repair system.
It is a further object of the present invention to provide such a measuring device which is compact to save space in the shop, and which is easily portable for use in different portions of a repair shop.
A still further object of the present invention is to conveniently establish a centerpoint from which comparative measurements can be made between corresponding left-side and right-side components even when no convenient bolt or other reference point on the vehicle body lies on the centerline.
These and other objects of the present invention will become more apparent to those skilled in the art as the description of the invention proceeds.